Method for reducing energy in the exhaust gas of blowing glass

ABSTRACT

An improved blow-head assembly for reducing the noise of high pressure gas issuing from a parison of heated glass being blown into a final form in a final shape mold. The gas which is used to blow the parison is exhausted from the parison, either in a counterbored area in which the gas inlet blow tube is positioned or through a plurality of axial openings, and introduced to an exhaust chamber through a plurality of radial openings. The gas initially impinges on a sound energy-absorbing felt metal material. Then, baffles direct the gas in a tortuous path to a plurality of exhaust openings. The net result is a significant reduction in the sound level of the exhaust gas.

' United States Patent [191 Jenkins Sept. 23, 1975 [5 METHOD FORREDUCING ENERGY IN THE 3,357,810 12/1967 Crouse 65/81 x EXHAUST GAS 0FBLOWING GLASS 3,652,253 3/1972 Small 65/262 X Inventor:

Pky., Toledo, Ohio 43607 [22] Filed:

Sept. 26, 1974 Appl. No.: 509,695

Related US. Application Data Division of Ser. No. 421,746, Dec. 5, 1973.

Charles W. Jenkins, 3456 Valleston US. Cl. 65/17; 65/62; 65/68;

References Cited UNITED STATES PATENTS Canfield 65/74 X Peiler Samuelsonet al 65/262 Primary E.\'aminer-S. Leon Bashore Assistant Examiner-FrankW. Miga [5 7] ABSTRACT An improved blow-head assembly for reducing thenoise of high pressure gas issuing from a parison of heated glass beingblown into a final form in a final shape mold. The gas which is used toblow the parison is exhausted from the parison, either in a counterboredarea in which the gas inlet blow tube is positioned or through aplurality of axial openings, and introduced to an exhaust chamberthrough a plurality of radial openings. The gas initially impinges on asound energy-absorbing felt metal material. Then. baffles direct the gasin a tortuous path to a plurality of exhaust openings. The net result isa significant reduction in the sound level of the exhaust gas.

1 Claim, 4 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of 23,907,533

US Patent Sept. 23,1975 Sheet 2 of2 3,907,533

FIG. 2

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METHOD FOR REDUCING ENERGY IN THE EXHAUST GAS OF BLOWING GLASSCROSS-REFERENCE TO RELATED APPLICATION This is a Division of co-pendingapplication Ser. No. 421,746 filed Dec. 5, 1973.

BACKGROUND OF THE INVENTION This invention generally relates to blowheads which introduce a gas under pressure to a plastic preform shape toexpend it into a final shape. More particularly, this invention relatesto a blow head for an IS type glass container forming machine.Specifically, this invention relates to an improved blow head of thetype described which significantly reduces the sound level of gas beingexhausted from the preform during the expansion process.

In the manufacture of objects from glass and thermo plastic materials, apreform shape in a plastic state is expanded in a final shape mold by agas under pressure introduced through a blow head. In particular, thewellknown IS machine is used to manufacture glass containers. In thisprocess, a preform shape or parison is expanded to its final shape in afinal shape or blow mold. During this process, high pressure gas entersthe parison and is exhausted, the exhaust being necessary to preventback-pressure generation and to cool the parison. In the past, thisexhaust gas generated a significant noise level. With the increasingemphasis on the improvement of industrial working environments, thenoise has become a problem. While the prior art contains somesuggestions for a solution, as noted in US. Pat. No. 3,137,560, theproblem had not been solved prior to my invention. Direct mufflingsystems generate too much back pressure or are too bulky. Passing theexhaust gas through a material such as fiber glass causes the fiberglass to rapidly become clogged. Steel wool is ignited by the hightemperatures of the exhaust. I have invented a compact and simple soundattenuation system for a blow head which impacts the exhaust gas on ametal felt to cause an energy loss and then directs the gas in atortuous route to eventual discharge to further decrease the gas energy.In addition, the area of the exhaust openings are preferably ten timesgreater than the area of the inlet openings to still further de creasethe gas velocity and consequently the exhaust noise level.

SUMMARY OF THE INVENTION My invention is an improved blow head assemblyfor injecting a gas under pressure from a source into a parisoncontained at least partially within a final shape mold to expand theparison into conforming relationship with the final shape mold. Onecomponent of the blow head assembly is a main body member which includesa first passage means for directing gas from the source into the parisonand a second passage means, communicating with the interior of theparison, for re moving gas from the parison after the introduction ofgas to the parison from the source. An exhaust chamber communicates withthe second passage means. The exhaust chamber is in communication withthe outside atmosphere. Sound energy-absorbing means are positionedwithin the exhaust chamber in a location such that gas from the parisonmust impinge on the energyabsorbing material before exiting from theexhaust chamber. The energy-absorbing material serves to partiallyabsorb the energy of the gas from the parison.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective viewof one embodiment of the present invention;

FIG. 2 is a cross-sectional elevation view of the embodiment of FIG. 1in an assembled configuration;

FIG. 3 is a cross-sectional elevation view of a second embodiment of thepresent invention; and

FIG. 4 is a fragmentary cross-sectional elevation view of a thirdembodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an exploded viewof one embodiment of the improved blow-head assembly, generallydesignated as 10, of the present invention. The blowhead assembly 10 hasas a major component a main body member 12, which is generallycylindrical in shape. The upper portion of the main body member 12 isformed with opposed bayonet locking lugs 14 and 15. The generaloperational environment of the blow-head assembly 10 may be seen withreference to US Pat. No. 2,282,848. The blow-head assembly 10 is held inposition on the arm which carries it by a bayonet-type lock which usesthe bayonet lugs 14 and 15. An axial opening 16 extends completelythrough the main body member 12 and is generally located centrally withrespect to the main body member 12. A blow tube 18 is inserted into theaxial opening 16 when the blow-head asembly 10 is in its operationalconfiguration. The blow tube 18 would be connected to a source ofcompressed gas, normally compressed air, for introduction into a preformor parison of molten glass. A relatively deep circumferential groove 20is cut from the material of the main body member 12. In the bottom ofthe groove 20 may be seen the outlets for a plurality of radial openings22 that are formed in the main body member 12. These radial openings 22may best be seen in FIG. 2. When assembled, the circumferential groove20 is closed by a cover means which may be the two semicircular coverplates 24 and 25. It should be pointed out at this time that the use ofa circumferential groove 20 and semicircular cover plates 24 and 25 isprimarily for the purpose of convenience in construction of theblow-head assembly 10. The muffling function, to be described later,could also be performed if the openings 22 were arranged in a lineararray rather than in the circumferential array in which they are shownin FIG. 1. The circumferential array allows economy in space and ease ofmanufacturing. The cover plate 24 has drilled completely through it apluality of upper openings 26 and a plurality of lower openings 27. Theother cover plate 25 likewise has a plurality of upper openings 30 and aplurality of lower openings 31. One of the important relationships ofthis invention is the ratio of the overall cross-sectional area of theopenings 26, 27, 30 and 31 to the cross section of the openings 22. Theratio of the area of the openings 26, 27, 30 and 31 to the area of theopenings 22 is preferably between 5 and 10 and, if possible, should beat least 10 or more. The cover plate 25 has an upper baffle member 32and a lower baffle member 33, each of the baffle members 32 and 33extending generally radially inwardly from the inside surface of thecover plate 25. The other cover plate 24 likewise has an upper baffle 36and a lower baffle 37, similar to the baffles 32 and 33. Note that thebaffles 32, 33, 36 and 37 are positioned such that the openings 26, 27,30 and 31 are above or below the various baffle members. This ensuresthat any gas which exits through the openings 26, 27, 30 and 31 mustfollow a tortuous path as defined by the baffles 32, 33, 36 and 37.Positioned between the baffle members 32 and 33 is an acousticalenergy-absorbing material 38. The energy-absorbing material 38 ispreferably a felt metaltype material which has a void percentage of fromtwenty percent to ninety percent. Preferably, the energy-absorbingmaterial 38 is a felt-metal material having an eighty percent voidratio. A preferred thickness for the energy-absorbing material isapproximately oneeighth of an inch thick. The pore size of theenergyabsorbing material 38 should be in the range of from 50 to500.microns. Suitable materials may be materials designated as FM-3l07or FM-l 107 supplied by the I-Iuyck Metals Company, 45 Woodmont Road,Milford, Conn. An energy-absorbing material 40 is likewise positionedbetween the baffle members 36 and 37 on the cover plate 24, and may beidentical to the energyabsorbing material 38. An opening 42 is drilledcompletely through the cover plate 25 between the two baffle members 36and 37. A corresponding opening 43 is provided through the cover plate24. A threaded bolt 46 may be inserted through the opening 43 to engagea threaded opening 48 formed in the main body member 12. This allows thecover plate 24 to be securely fastened in place on the main body member12. A corresponding bolt 49 may be inserted through the hole 42 in thecover plate 25 to engage a threaded hole, which is not visible in FIG.1, in the body 12 to secure the cover plate 25 to the main body member12. An upper lip 50 and a lower lip 51 (see FIG. 2) may be provided foraccurately seating the cover plates 24 and 25 in a desired location. Afinal feature of the blow-head assembly is a relatively large recessedarea 52 at the lowermost portion of the blow-head assembly 10. Therecess 52 is used to provide clearance over the finish of a glasscontainer, as will be seen in FIG. 2. It should be noted that the recess52 is not an essential part of the present invention, and shouldoperating circumstances dictate that the finish portion of a containerbeing blown into its final shape should be contained completely withinthe mold, the recess 52 would not be required.

With respect now to FIG. 2, those skilled in the art are aware that aparison or preform shape 54, having a finish portion 55, is placed in afinal shape mold 56. In the final shape mold 56, a gas under pressure,preferably compressed air, is injected into the parison 54 to cause theparison 54 to expand into a conforming relationship with the final shapemold 56. Note that the finish portion 55 fits within the recessedportion 52 of the main body member 12 since the finish portion 55extends abovethe finish shape mold 56. The gas under pressure isintroduced through the blow tube 18, which may now be seen is insertedinto the axial opening 16, in a conventional and well-known fashion. Thegas then enters the parison 54 and expands the parison into a conformingrelationship with the shape of the interior cavity of the finish mold56. The gas within the mold obviously must be exhausted to prevent abuildup of back pressure, and to provide for this exhaust, the axialopening 16 has a slightly expanded diameter counterbore 58 in its lowerportion adjacent to the parison 54. Gas exiting from the blow tube 18then moves up coaxially along the blow tube 18 in the expandedcounterbore 58 until it reaches the openings 22. As previously noted,the openings 22 are radial openings which communicate with thecounterbore 58. The gas then exits from the radial openings 22 andimmediately impinges upon the energy-absorbing materials 38 and 40. Thisimpingement upon the energy-absorbing materials 38 and 40 causes the gasto lose much of its velocity energy and achieves a substantial velocitydecrease of the flow of gas. Then, the gas must follow a tortuous patharound the baffles 32, 33, 36 and 37 to eventually exit through theopenings 26, 27, 30 and 31. It will be noted that with the cover plates24 and 25 in position over the circumferential groove 20, an exhaustchamber is thereby defined. In most general terms, one may con sider thecounterbore 58 and the radial passages 22 to be a second passage meansformed within the main body member 12 for removing gas from the parison54 and passing this gas into the exhaust chamber. The primaryattenuation of the sound occurs because the high velocity air impingeson the energy-absorbing materials 38 and 40 which are chosen to createmaximum noise attenuation in the high frequency range where the noise ismost objectionable. (see The Generation of Sound by Aerodynamic Meansby'N. Curle, Journal of the Royal Aeronautical Society, November, 196l).This, in combination with the Helmholtz Resonator effect created by thetotal exhaust chamber, causes the major decrease in noise level. Theopenings 26, 27, 30 and 31 ensure that this decreased noise level ismaintained. Because these openings are so much greater in acrosssectional area than the openings 22, the air exits to theatmosphere at a relatively low velocity, thus preventing noisegeneration as a result of air stream velocity. The net result of thistotal configuration is that the noise of the gas exiting from theparison is substantially re duced. Under actual field test conditions, anoise level of from 97 to 100 db was measured with a standard blow headin use. With the improved blow-head assembly 10 of the present inventionin use, the sound level was reduced to 89 db, which was the backgroundnoise level. Therefore, it is possible that the improved blowheadassembly of the present invention may reduce the :overall noise leveleven more than is indicated by the measurements, since an accuratemeasurement of the precise degree of noise reduction was not possibledue to the background level.

FIG. 3 illustrates a somewhat modified blow-head assembly 10' similar tothat shown in FIG. 2. The majority of the components in FIGS. 2 and 3are similar or, in fact, identical, and therefore primed numbers will beused in FIG. 3 for elements that are similar and easily recognizable ascomparable elements in FIG. 2. The embodiment shown in FIG. 3 isparticularly useful in the event that a parison 54' is to be blown in afinal shape mold 56' with a wider finish portion 55' than the finishportion 55 shown in' FIG. 2. In such a situation, the blow tube 18 isnot required. Thus, as seen in FIG. 3, the axial opening 16' itselfserves as a first passage means for directing gas from the source intothe parison 54. In addition, it will be noted in FIG. 3 that thecounterbore portion 58 near the lower portion of the axial opening 16 inFIG. 2 is not present in FIG. 3. The axial opening 16 in FIG. 3 extendsthrough substantially the entire length of the main body member 12'without a change in dimension. At the lower end of the axial opening 16,a plurality of axially extending openings 60 are opened to communicatewith the interior of the parison 54'. These axial openings 60 thencommunicate with radial openings 22 which again direct the jets of gasfrom the interior of the parison 54 into an impacting relationship withacoustical energyabsorbing material 40' and 38. The energy-absorbingmaterial 38 is held in position between upper and lower baffle members32' and 33' in a cover member 25. The energy-absorbing material 40 isheld in position between upper and lower baffle members 36' and 37' in acover member 24. The operation of the exhaust chamber and mufflingeffect is identical in FIG. 3 with that previously described in FIG. 2,and it is believed that a detailed explanation of this muffling effectis not required again. It also may be appreciated that the plurality ofaxial openings 60 and the plurality of radial openings 22 may beconsidered to be a second passage means which communicate with theinterior of the parison 54' for removing gas from the parison after theintroduction of the gas into the parison from the source of gas.

FIG. 4 illustrates an embodiment of the present invention which may beused on existing blow heads. The previously illustrated embodimentsobviously require some modification to the standard blow-head body. InFIG. 4, te circumferential groove has been elimi nated. In this case,gas from the parison may flow around a blow tube 18 in an expandeddiameter counterbore portion 58 of an axial opening 16". The gas thenflows outward in a plurality of radial openings 22". The openings 22"are open to the outside of a main body member 12". An exhaust chamber isdefined by a hollow annular ring member 62. The ring member 62 issecured to the body member 12" in any convenient manner, such as withthreaded bolts. The ring member 62 has upper and lower baffle members,respectively 36" and 37". An acoustical energyabsorbing material 40" ispositioned between the baffle members 36" and 37". The gas exiting fromthe openings 22" will impact on the energy-absorbing material 40" toachieve an energy reduction function as previously explained. Afterpassing around the baffle members 36" and 37", the gas may exit to theatmosphere through upper openings 26" and lower openings 27" in the ringmember 62. The configuration shown in FIG. 4 may be just as effective innoise attenuation as those previously shown and described, but may beused on existing blow heads with minimal modification thereof.

1 claim: l. A method for reducing the noise generated by the exhaust ofgas under pressure from a parison being blown into conformingrelationship with a final shape mold, which comprises the steps of:

directing said exhaust gas from said parison through a plurality ofopenings;

reducing the energy of said exhaust gas from said parison by directingsaid gas onto an energy-absorbing material;

constraining said reduced energy gas to a tortuous path of travel tostill further reduce the energy thereof; and

directing said reduced energy gas into the atmosphere.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3 907533 DATED September 23, 1975 |Nv 0 (5) Charles W. Jenkins It iscertified that error appears in the above-identified potent and thatsaid Letters Patent are hereby corrected as shown below:

In the Heading Should show this patent assigned to Owens- Illinois,Inc., Toledo, Ohio 43666.

Column 5, line 26, change "te" to read ---the---.

Signed and Sealed this t wenty-third D3) of December 1975 [SEAL] A ttest:

RUTH C. MASON (nmmissioner ufPatenIs and Trademarks

1. A METHOD FOR REDUCING THE NOISE GENERATED BY THE EXHAUST OF GAS UNDERPRESSURE FROM A PARISON BEING BLOWN INTO CONFORMING RELATIONSHIP WITH AFINAL SHAPE MOLD, WHICH COMPRISES THE STEPS OF: DIRECTING SAID EXHAUSTGAS FROM SAID PARISON THROUGH A PLURALITY OF OPENINGS, REDUCING THEENERGY OF SAID EXHAUST GAS FROM SAID PARISON BY DIRECTING SAID GAS ONTOAN ENERGY-ABSORBING MATERIAL, CONSTRAINING SAID REDUCED ENERGY GAS TO ATORTOUS PATH OF TRAVEL TO STILL FURTHER REDUCE THE ENERGY THEREOF, ANDDIRECTING SAID REDUCED ENERGY GAS INTO THE ATMOSPHERE.